A method for preparing a substance and a device that can be used for this purpose are known from AT 510 753 B1.
In the method for preparing a substance (pulp or waste paper) that is known from AT 510 753 B1, the pulp or the waste paper is dissolved in a pulper to form a pulp suspension. In this case, the procedure is to be performed in such a way that the isolation and deflaking of the fibers is carried out by dispersing the pulp suspension, a flow is generated during dispersing in the pulp suspension, a flow is generated during dispersing to fibrillate the fibers in the pulp suspension, which flow is directed downward inside the pulp suspension and is directed outward in the lower area of the pulp suspension, the flow that is directed outward is directed against static baffles, and a shearing of the fibers of the pulp and the fibrillation are carried out in the outward-directed flow to the fibers in the pulp suspension.
The device for dispersing a pulp suspension, known from AT 510 753 B1, comprises a container, baffles that point radially into the interior of the container, a rotor provided in the container, devices on the rotor for generating a flow of the pulp suspension that is directed radially outward in the container, and a propeller for generating the flow of the pulp suspension that is directed downward.
A device for mixing, kneading, fibrillating, grinding and macerating materials is known from EP 1 287 878 A2. The known device comprises a container in which a stator is equipped with gear rims and a rotor is equipped with teeth. The teeth of the rotor interact with the teeth of the gear rims of the stator. A guide hopper, which is to concentrate the material flow moving from above to the middle area of the container, projects between the arms of the rotor. The outside surface of the guide hopper bounds an annular gap that throttles the material flow.
In the case of the device of EP 1 287 878 A2, no forcible control of the product flow is achieved by the active zone of the teeth on the rotor and stator. It is problematic in the known device that the product flow often does not reach the rotor or deviates upward from the actual operating area of the teeth on the rotor and the teeth on the stator between the rotor arms, without the product flow being affected. This means that in the case of the device according to EP 1 287 878 A2, a majority of the product flow that is to be processed circulates in an incompletely processed manner in the container.
DE 27 22 906 A1 relates to a unit for deflaking substance suspensions for paper-making machines. The unit comprises multiple deflaking devices, each of which is equipped with a stator and a rotor, which devices have interlocking rows of teeth with teeth and slots located in-between. Any measures to guide the flow path of the substance suspension for the purpose of achieving an effective and complete deflaking are not provided in the unit according to DE 27 22 906 A1.
From U.S. Pat. No. 2,823,871 A, a multi-stage mill is known, in which a steeply conical premilling zone and a flat, disk-like end-milling zone are provided. The end-milling zone comprises annular grinding elements, which are put into motion relative to one another.